Visual evoked potentials in subgroups of migraine with aura patients

Abstract

BackgroundPatients suffering from migraine with aura can have either pure visual auras or complex auras with sensory disturbances and dysphasia, or both. Few studies have searched for possible pathophysiological differences between these two subgroups of patients.MethodsMethods - Forty-seven migraine with aura patients were subdivided in a subgroup with exclusively visual auras (MA, N = 27) and another with complex neurological auras (MA+, N = 20). We recorded pattern-reversal visual evoked potentials (VEP: 15 min of arc cheques, 3.1 reversal per second, 600 sweeps) and measured amplitude and habituation (slope of the linear regression line of amplitude changes from the 1st to 6th block of 100 sweeps) for the N1-P1 and P1-N2 components in patients and, for comparison, in 30 healthy volunteers (HV) of similar age and gender distribution.ResultsVEP N1-P1 habituation, i.e. amplitude decrement between 1st and 6th block, which was obvious in most HV (mean slope −0.50), was deficient in both MA (slope +0.01, p = 0.0001) and MA+ (−0.0049, p = 0.001) patients. However, VEP N1-P1 amplitudes across blocks were normal in MA patients, while they were significantly greater in MA+ patients than in HVs.ConclusionsOur findings suggest that in migraine with aura patients different aura phenotypes may be underpinned by different pathophysiological mechanisms. Pre-activation cortical excitability could be higher in patients with complex neurological auras than in those having pure visual auras or in healthy volunteers.

Frequency‐Dependent Habituation Deficit of the Nociceptive Blink Reflex in Aura With Migraine Headache. Can Migraine Aura Modulate Trigeminal Excitability?

“…As a novel aspect, our study demonstrated in AwMH subjects during the interictal period a deficit of habituation of nociceptive trigeminal responses largely resembling that observed in MWoA subjects of comparable clinical severity. These data are in line with previous observations of deficit of habituation of evoked responses derived from repeated stimulation of visual cortex in subjects with migraine aura during the interictal phase . The habituation deficit of nociceptive trigeminal reflex responses in both MWoA and AwMH permits to hypothesize that these two forms of migraine share a common, probably genetically determined, pathogenic substrate.…”

“…These data are in line with previous observations of deficit of habituation of evoked responses derived from repeated stimulation of visual cortex in subjects with migraine aura during the interictal phase. 21,22 The habituation deficit of nociceptive trigeminal reflex responses in both MWoA and AwMH permits to hypothesize that these two forms of migraine share a common, probably genetically determined, pathogenic substrate. However, it must be noted that in AwMH subjects, the habituation deficit of the trigeminal nociceptive reflex responses was less pronounced than that observed in subjects with MWoA, although without reaching a significant statistical level.…”

Excitability of the motor cortex in patients with migraine changes with the time elapsed from the last attack

“…This findings is consistent with previous evidence obtained with psychophysiological tests [24], neuroimaging techniques [25, 26], and cortical EPs [4–6] showing that during the variable pain-free period between two migraine attacks, the brain of an individual with migraine is exposed to subtle cyclic functional changes. Indeed, at the cortical level, we previously observed that patients with MO and a subgroup of patients with migraine with visual aura associated with paraesthesia and/or dysphasia exhibited a strong decrease in EP amplitude habituation during the stereotyped presentation of visual stimuli with the passing of time from the last attack [4, 5]. The results of the present study revealed that the same correlation is valid for the resting excitability of the motor cortex in response to single-pulse TMS.…”

Alice in Wonderland Syndrome: A Clinical and Pathophysiological Review

“…In a study on patients with migraine with complex aura (comprising not only visual but also sensory and language dysfunctions), a higher level of dysfunction in comparison to patients with simple aura, correlating higher interictal abnormalities with more complex aura pattern CSD, was found [57]. Also, increased VEP amplitude was correlated with a longer distance in the spreading of paroxysmal EEG responses [58].…”